Though there are lesser devices using these CPU architectures there are some advantages:
This feature can use a big APK or separated APKs. Google Play supports multiple APKs for the same app, making app downloading more lightweight.
X86 is solved. Can also add mips and armeabi easily if you want now. (only need to figure out the correct toolchain name ^^)
-march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3